Replies

1. 
   DANL | Jun 13, 2005 03:49pm | #1

   Questions similar to this are asked quite a lot. If you use the search feature at top or bottom of the list of discussions and put in a key word like "sistering" you can get a list of previous discussions about this. The usual argument seems to be that sistering like-sized joists has a minimal effect. Some recommend putting new joist between old ones, others say to use blocking, others talk about strongbacks and so forth. Many will tell you the real solution is to put a beam and posts under the center of the floor if possible. Anyway, if you look at past discussions, it'll start you out. Probably others will answer you directly too. Welcome, and good luck!

1. 
   clouts69 | Jun 13, 2005 09:37pm | #3

   Thanks Danno. I'll look into it.

2. 
   CapnMac | Jun 13, 2005 09:29pm | #2

   Danno makes some excellent points.

   What sort of access do you have to the floor joists?

   If they are open, how "open" are they (open everywhere but the kitchen & bathroom can sometimes not be open "enough")?

   While we're cogitating on this, what sort of "stuff" is is in the existing joist bays?  It will not help if there's half a house's plumbing or hvac work to move to get a stiffer floor in.

   Now, looking here:  http://www.southernpine.com/pdf/table01.pdf, just to pick a span table, doubling your 2x6 (so you have about 10-11" O.C.) is still "short" of your 14' span, and that's at a relatively light 30# live load.  That suggests (to me) that you may need a bit of engineering.  It's that, or lose a couple or three inches of headroom, possibly.

   Occupational hazard of my occupation not being around (sorry Bubba)
1. 
   clouts69 | Jun 13, 2005 09:53pm | #4

   The house is rustic (read as uncovered walls) and access is clean. The house was built in pieces so the kitchen has no upper floor to support. It was added as separate addition years later. Also, there is minimal "stuff" in between the joists. There is some wiring but it is contained at the ends.

   What do yo mean by lose a few inches of headrom? Apply a couple of layers of subflooring upsatirs or adding wider joists and lose the headroom downstairs? FYI, the joists aren't 2x6. They are literally 2" thick and 6" wide. They are rough sawn so I guess he may have cut them himself.

1. 
   DANL | Jun 13, 2005 10:54pm | #5

   You didn't ask this of me, but I think you'd be ahead to add deeper joists (whatever the span table says--2x8 or 2x10) rather than add more weight by adding more layers to the second floor. Just "gut level" feeling says that whatever stiffness you might gain by adding layers, you will lose because of the additional weight. If you won't be bumping your head, I would think adding deeper joists between, or sistering deeper joists would be good--but you will have to notch the ends of deeper joists to fit between the existing floor and the top of the wall and I'm not an engineer, but others may be able to tell you if that could be a problem. You are allowed to notch to a certain depth by code and I'm not certain what it is at the moment.

2. 
   CapnMac | Jun 14, 2005 12:52am | #7

   lose a few inches of headrom

   Well, if the answer is to add 14' 2x10 and sister them to the existing joists, then you'd have a 1.5 wide by 9.25 tall (not entirely "pretty") structural member fastened to the side of your existing 2 wide by 6 tall hewn joists.  Since the floor is fixed, the difference in height, 3.25" in this example sticks "down" into the headroom below.

   If the joists are 144" (12') above the floor, not a big deal; if they were 92, 93" up, though, could be an issue.  (And that before havign to notch them to sit on the existing top plate.)

   Adding flooring above is not likely to take the bounce out, you'd need some sort of stressed skin on both sides to do something like that.  Which would also necessitate an answer I was trying to avoid for you--pulling up all of the existing upstairs floor.Occupational hazard of my occupation not being around (sorry Bubba)

3. 
   rez | Jun 13, 2005 11:50pm | #6

   clout-

   That subject has been addressed here on Breaktime a number of different times in the past.

   In the event you fail to receive the information you desire, you might find it in the archives.

   If you scroll down in the lower left corner of your screen there is a search function that will take you to previous threads dealing with whatever you type in the search bar.

   If you type in 'bouncy floor'  or other keywords of the subject matter you'll get a supply of data from those old threads.

   Cheers

   A person with no sense of humor about themselves is fullashid
   
   

    

4. 
   Piffin | Jun 14, 2005 07:44am | #8

   oughta be 2 x 10s at 16" oc. Might get by with sistering 2x8s to what you have, but better try to find room for 2 x 10 sisters

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

5. 
   doodabug | Jun 16, 2005 01:13am | #9

   Where are you located? I have worked on three rustic cabins in Michiana Shores, Indiana. New wood will never look good if you want to keep the rustic look. I used rough sawn cedar for repairs and it looked OK. I would leave the bounce. Around here we call that character. Like squeaky floors and stairs. If you have headroom and really don't like the bounce you could put a timber beam under at midspan.

   Exposed rafters, joists, studs like a timber frame?

1. 
   clouts69 | Jun 17, 2005 04:18am | #10

   Located in Southern NH. That was one of my concerns--having the wood contrast so much.

   A beam is a possibility. Thanks.

1. 
   doodabug | Jun 18, 2005 07:48pm | #11

   You can see one of the ones I worked on. Go to http://www.seemichiana.com. click properties, click michiana log cabin, click view details. let me know if it resembles yours.

1. 
   clouts69 | Jun 20, 2005 01:30am | #12

   Yeah, it is quite similar although mine is a cedar-sided house. Central air?? What, open all the windows?? :)

   Here is mine.

   http://members.cox.net/cathyabb/index.htm